Zero Clearance Side Seals
 

I like to set up my side seals as tight a practical. There are different thoughts on this minimum spec.
I have seen recommendations from .002” -.004” for turbo applications.

On my last engine build-up I mistakenly switched two side seals causing a
.002” clearance. This resulted in scrapping the RE front plate because of a
.004” wear groove on it in the area of combustion (where heat/expansion is greatest).

I decided to try .000”! Found this in an early Mazda paper.

What do you think?
Barry

The problem I see is the chance for the side seal to get jammed and loose compression on one face.

Dan

Mazda's race prep manual lists .0039" to .0059" for 13Bs. But this is from 1996.
I do not know if this has changed.

Thats kind of a cool idea

Yes Chuck you are right, but the regular workshop manual states .002"-.0059" and Racing Beat recommends .0015”-.004”( this may be a NA spec).

I guess I should have said it runs gap-less. It still has clearance to expand into the added corner seal slot.

Barry

Just thinking out-loud here....and I'm in the middle of only my first rebuild so go easy....
What about potential carbon build-up in that corner seal slot. I see some clearance for length, but is there risk with loss of what little "side" clearance there is within that slot due to expansion and/or carbon? What would be the result of the side seal and corner seal being effectively fused together if that happened?

My swag (scientific wild ass guess) would be that it wouldn't much more of a problem. I'll have to tell you in a couple of years.


Barry

I'd have to go check the feeler gauges, but I'm pretty sure I clearance side seals at .0015 to .002. Nice and tight, and havent had a problem yet. Of course, we recommend a pretty long breakin period of 1500 miles before serious boosting.

This is the way to get a precision cut.

Barry

http://i287.photobucket.com/albums/l...algrinding.gif

http://www.rotarycarclub.com/attachm...7&d=1206964763
Pretty neat barry!

So, are you going to be ready for DGRR??

seems cool..

Those special coner seals should seal better, but where can you buy them?
If you had a good machine shop, maybe you could make them yourself.
The question is, where they not cost effective for Mazda, or only used in rcae engines?

Yes Chuck, I am not sure why Mazda hasn't used them for production. Possibly the extra machining and fitting.

I also wonder if the reason could be that the normal blow-by of the side seals might help to float the rotor between the housings.

As for who makes them, I make them myself with a special diamond cutting tool. I can cut a set for you.
Barry

Phil, thanks for installing the picture correctly for me. How do you do that?

Barry

And I am still building my engine but expect to be there. I may have to go with Jack.

Barry,

Neat idea, but what about Apex seal clearance, assuming you had more clearance at the apex seal (two faces) you would see unwanted binding at the side seal from the apex seal rotating at the point of peak combustion pressure. Only one way to find out, and that's to test it out.

If money was no object, zero clearance on everything after Nikasil coating, or something of similar low friction properties. Ceramic coating......

i was thinking the same. cant really avoid it(by cutting out more space to move) and keep the seal tight, so if theres any rotation of the corner seal it may cause binding and eventually wear the broad surface of the side seals.

I cut each side seal to the specific rotor location. Unfortunately each rotor corner is slightly different. I then rock the apex seal to check for binding of the side seal. If any is found I increase the cut on that side.

One advantage I noticed was that on final assembly the apex seal always slides in fully. It is perfectly aligned. No fishing with a pick to straighten the lower corner seal position!

Barry

I was at Barry's last week, he is the wizard!

I am seriously hoping he is ready, if not I think he should ride with Jack!

/hijack..... Hey Barry I fixed that a/c!

I'm not too familiar with engine work but what's the benefit of this?

More compression.

Here is a poor picture of leak from my last .003” clearanced side seals (cleaned by 50/50 water/meth).

Notice the clean trailing side vs. the leaking leading end.

Barry

http://i287.photobucket.com/albums/l...5-2540_IMG.jpg

I see the difference between the trailing (right side) and the leading (opposite) sides of the rotor and that was due to the large clearance you had before between the side seal and the corner seal.

So, the larger corner seal (with the groove in it for the longer side seal) lowers compression by....?

I'm looking at this pic (no access to the FSM for specs right now) and I can see how your corner seal(s) are different but since I'm not familiar with internals I don't fully grasp how the compression is lowered by reducing/eliminating the clearance.

http://rotarycarclub.com/attachment....2&d=1206700401

http://www.turborx7.com/images/rebuild/Specs11b.jpg

I'd love to hear more about his when you have time.

The gapless corner seal doesn't leak any compression!

http://i287.photobucket.com/albums/l...cesideed-2.jpg

The leaking seal was set-up with a tight clearance of .003", the Factory minimum.

http://i287.photobucket.com/albums/l...5-2540_IMG.jpg

Barry

This is an awesome intriguing idea. I saw on your same thread on the other place that you're not running this. How is it doing? What side seals are you using?

The trimmed version of the Mazda side seal is part number is N3Y1-11-C11. There is a longer untrimmed version, but Ray Crowe could not find it. He ordered an older number but it turned out to be thicker (.8mm instead of .7mm).

Does anyone know this untrimmed part number?
Barry

Wouldn't that raise compression due to no escaping (or what not) air?

Yes, it gives higher cranking pressure and running pressures!
Barry

Oh, earlier you said less compression. I got confused. :D

That's what has me :confused:. My brain says compression is maintained constant if there is no clearance for the seals to flex so I don't see how compression is lowered.

I'm also waiting on an email to see if I can get a hold of that SAE article.

He misspoke earlier, it appears. It does raise compression.

I have access to all the SAE documents here............. they're just on Microfiche..... :banghead::banghead::banghead::banghead:

well I was able to access SOME SAE Papers but the one you need (regarding cooling) is not there. I'll keep looking.

I found the paper in my stacks of stuff...

I looked back through the post looking for where I said that you get less compression. Help me find it and I will correct it.

We want to seal the rotor chamber as well as possible. This makes the engine start better, run crisper, and of course, gives more ultimate horsepower!

Barry

Post 20.

Thanks Rob, I changed it to more compression.

I meant that the gap type cornerseal would leak and lead to less compression but I see it was misleading.

Barry

:icon_tup:

Really?
You gonna resurrect a thread from 7 years ago???

Geez Barry, you're breaking one of the most oldest netiquette rules out there.

Please stop doing this.

Thread closed.
You're welcome to reopen another thread - hell, even identical title if you want.

You're asking what would've been the proper way to handle this?
1) Start new thread...
2) Reference new thread back to the old thread...
NOTE: Try and leave threads that are inactive over a year - most definitely over TWO YEARS - alone.


-Ted

1. Publicly attacking the administration's actions when it comes to administrative forum issues. Internal issues are just that, INTERNAL. PM the appropriate channels and discuss the problem and solution without making a heated an e-fight about it.

:icon_no2:

Barry, leave it alone.
You're acting like a baby.

LEAVE THE THREAD CLOSED.


-Ted

You two are trolling an informational thread.